Formation of Self-Assembled Nanowires from Copper Nanoparticles Synthesized by the Electro-Explosion of Wires Technique-Study of the Time-Dependent Structural and Functional Evolution.

We report here the formation of Cu nanowires (CuNWs) from Cu nanoparticles (CuNPs) by a self-assembly process. The CuNPs were synthesized by the electro-explosion of wire (EEW) technique that included nonequilibrium processes for the synthesis. Structural evolution in terms of aggregation or nanowire formation in the samples was observed when the CuNPs were kept for a month after synthesis in a glass vial without the application of any external driving force. The emergence of tangled CuNWs was noticed at the bottom of the vials only when no agitation or aeration was allowed. The nanowires were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Thermal oxidation of the nanowire samples implied that they could convert into rod-shaped structures. Loss of functionality was also observed in the hemoglobin precipitation study conducted to compare the activity of freshly prepared CuNPs and CuNWs. From the above observations, we conclude that the CuNP, after synthesis, possesses a huge amount of energy, and attainment of equilibrium occurs through either aggregation (clustering) or ordered self-assembly, depending on the conditions applied.